I didn't figure the question was about tuning the DCT, rather what ESS had available for the E89 w DCT. I asked them the same question directly and got the below response. But your r right, it's odd that they call it the stage 1 when it makes the same power as their stage 2 for non DCT trannies.

Per Asbjorn w ESS-
"The DCT version of the Z4 3.5is can only take the power of the Stage 1 (400chp, ~350rwhp). Any more and the DCT clutches can not handle it in the long run."

I think there is an typo here as Stage1 gives around 355 chp and 480 tq and Stage 2 390-400 chp and 550 tq, anyway as i remember it. Ceartinly can feel the difference between the stages.

Getrag can take 600tq what i have learned ( there is a link somwhere on the forum)

Whatever is true, parts will always deteriorate when used. I belive how you use it will be more of a factor of how long parts will hold.

I am still confused

Manual says don't use "launch control" to much as it increases the load on the car, even without ecu tunes!